N Ganga Bhavani Yaswanth Kalepu : September 2013

Matlab R2008a is The Software to be used to Run the Program

1.Program to Understand Standing waves with Different Reflection Coefficients

clc;
clear all;
close all;
% V=Voplus*cos(wt-beta*z)+Vominus*cos(wt+beta*z);
%(Vominus/voplus=Ref)
lamda=input('Wavelength of Wave');
u=input('Velocity of wave in Medium');
Ref=input('Reflection Coefficient');
Voplus=input('Forward Travelling wave real');
f=u/lamda;%frequency of EM wave
beta=2*pi/lamda;%propagation Constant
Vominus=Voplus*Ref;
z=-2*lamda:lamda/100:0;
figure(1);
hplot=plot(z,zeros(1,length(z)));
axis([-2*lamda 0 -2*Voplus 2*Voplus]);
grid on;
t=0;
VSWR=(1+abs(Ref))/(1-abs(Ref));
% for j=1:1000 % for Observing the Wave motion with time and Space
% V=real(Voplus*exp(1i*(2*pi*f*t-beta*z))+Vominus*exp(1i*(2*pi*f*t+beta*z)));
% set(hplot,'YData',V);
% pause(0.001);
% t=pi/(2*pi*f*20)+t;
% end;
for j=1:100 % for observing the wave Amplitute Spane in Space
V=real(Voplus*exp(1i*(2*pi*f*t-beta*z))+Vominus*exp(1i*(2*pi*f*t+beta*z)));
plot(z,V);
hold on;
pause(0.001);
t=pi/(2*pi*f*50)+t;

end;

Given:
Wavelength of Wav : 3
Velocity of wave : 12345678
Reflection Coefficient : 0.5
Forward Travelling
wave Magnitue : 12

2. Program to understand Transmission lines with different loads and Transmission Parameters

clc;

clear all;

close all;

% Given Length of Transmission Line 'L', Propagation Constant 'Gamma',

% Characteristic impedance 'Zo', Input Voltage i.e Vin Cos(2*pi*ft) 'Vin', Source impedance Zs,

% Load Impedance 'ZL',Input frequency 'f'.

L = input('Length of Transmission Line ');

gamma= input('Propagation Constant');

Zo=input('Characteristic Impedance of Tx Line');

Vin=input('Input Voltage Amplitude');

Zs=input('Source impedance');

ZL=input('Load impedance');

f=input('Input Frequency');

RefL=(ZL-Zo)/(ZL+Zo);

Zin=Zo*(ZL*cosh(gamma*L)+Zo*sinh(gamma*L))/(Zo*cosh(gamma*L)+ZL*sinh(gamma*L));

Vzo=Vin*Zin/(Zin+Zs);

Izo=Vzo/Zin;

Voplus=(Vzo+Izo*Zo)/2;

Vominus=(Vzo-Izo*Zo)/2;

z=0:L/100:L;

figure(1);

hplot=plot(z,zeros(1,length(z)));

axis([0 L -2*Vin 2*Vin]);

grid on;

t=0;

VSWR=(1+abs(RefL))/(1-abs(RefL));

for j=1:10000

I=(((Voplus*exp(-gamma*z))/Zo)-((Vominus*exp(gamma*z))/Zo))*exp(1i*2*pi*f*t);

V=((Voplus*exp(-gamma*z))+(Vominus*exp(gamma*z)))*exp(1i*2*pi*f*t);

set(hplot,'YData',real(V));

pause(0.001);

t=pi/(2*pi*f*20)+t;

end;

Given:

Length of Transmission Line: 3

Propagation Constant : 0.2+5i

Characteristic Impedance : 50

of Tx Line

Input Voltage Amplitude : 12

Source impedance : 30

Load impedance : 100+60i

Input Frequency :1000000

when you run the program you can see a motion picture

3. Program to understand Transmission lines with different loads and Transmission Parameters with drawing all possible values the voltage can take as a function of length.